Willow Slough Dam dam
Willow Slough Dam
Willow Slough Dam, located in Mills County, Iowa, was completed in 1959 and is owned by the state. The dam is primarily used for recreation purposes and has a storage capacity of 1600 acre-feet. With a height of 8 feet and a surface area of 2100 acres, the dam sits on the TR-West Nishnabotna River and is regulated by the Iowa Department of Natural Resources.
The dam, classified as an earth dam with a soil foundation, has a low hazard potential and a moderate risk rating. Although it has not been inspected since 1963, the dam is still considered to be in good condition. In case of emergencies, the dam does not have an Emergency Action Plan (EAP) prepared. Overall, Willow Slough Dam provides recreational opportunities while also serving as a key water resource management structure in the area.
Water resource and climate enthusiasts interested in Willow Slough Dam will find it to be a valuable asset in the conservation and management of water resources in Mills County, Iowa. The dam's presence on the TR-West Nishnabotna River not only offers recreational activities but also plays a crucial role in regulating water flow and storage in the region. Despite its age, the dam continues to function effectively and has a moderate risk rating, highlighting its importance in maintaining water security and safety in the area.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Willow Slough Dam -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| East Nishnabotna River At Red Oak | 588 cfs | → |
| West Nishnabotna River At Randolph | 693 cfs | → |
| West Nishnabotna River At Hancock | 313 cfs | → |
| East Nishnabotna River Near Atlantic | 219 cfs | → |
| Missouri River At Omaha | 29,100 cfs | → |
| Weeping Water Creek At Union | 17 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Willow Slough Dam.
Track Willow Slough Dam in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Willow Slough Dam
Where does the data for Willow Slough Dam come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Willow Slough Dam.